1. Field
This disclosure relates generally to the field of communications and more specifically to the system and methods for regulating frequent cell reselections by idle-mode mobile devices.
2. Background
Wireless communication systems are widely deployed to provide various types of communication content such as, for example, voice, data, and so on. Typical wireless communication systems may be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access systems may include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and the like. Additionally, the systems can conform to specifications such as third generation partnership project (3GPP), 3GPP long term evolution (LTE), ultra mobile broadband (UMB), evolution data optimized (EV-DO), etc.
Generally, wireless multiple-access communication systems may simultaneously support communication for multiple mobile devices. Each mobile device may communicate with one or more base stations (e.g., which can be commonly referred as macrocells) via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to base stations. Further, communications between mobile devices and base stations may be established via single-input single-output (SISO) systems, multiple-input single-output (MISO) systems, multiple-input multiple-output (MIMO) systems, and so forth. In addition, mobile devices can communicate with other mobile devices (and/or base stations with other base stations) in peer-to-peer wireless network configurations.
To supplement conventional base stations (e.g., macrocells), additional low power base stations can be deployed to provide more robust wireless coverage to mobile devices. For example, low power base stations (e.g., which can be commonly referred to as Home NodeBs or Home eNBs, collectively referred to as H(e)NBs, femto nodes, femtocell nodes, pico nodes, micro nodes, etc.) can be deployed for incremental capacity growth, richer user experience, in-building or other specific geographic coverage, and/or the like. In some configurations, such low power base stations are connected to the Internet via broadband connection (e.g., digital subscriber line (DSL) router, cable or other modem, etc.), which can provide the backhaul link to the mobile operator's network. In this regard, low power base stations are often deployed in homes, offices, etc. without consideration of a current network environment.
In a mixed macrocell/femtocell deployment, frequent idle-mode system reselections between macrocells and collocated femtocells can happen by a fast moving mobile device (e.g., a vehicular mobile device) entering and leaving patchy femtocell coverage and/or mobile device ping-ponging between a macrocell and collocated femtocells due to channel fading. Frequent system reselections are not desirable because they can lead to frequent mobile device registrations on different systems, which in turn may cause device battery drainage, increase in signaling load, missing of pages, and other problems that adversely affect transmission and processing of data and hence user experience. Therefore, it is desirable to regulate system reselection process for idle-mode mobile devices with the objective to reduce a ping-pong effect during wireless system reselection.